Due to geological processes such as sedimentation, tectonic movement, and backfilling, natural soil often exhibits characteristics of rotated anisotropy. Recent studies have shown the significant impact of rotated anisotropy on slope stability. However, little research has explored how this rotated anisotropy affects the large deformations occurring after slope failure. Therefore, this study integrates rotated random field theory with smoothed particle hydrodynamics (SPH) to investigate its influence on post‐failure slope behavior. Focusing on a typical slope scenario, this research utilizes graphics processing unit (GPU)–accelerated covariance matrix decomposition (CMD) method to create rotated anisotropy random fields and applies the SPH framework for analysis. It examines the influence of rotated anisotropy angles and the cross‐correlation between cohesion and internal friction angle on landslides. The results indicate that the rotational anisotropy of the slope significantly influences post‐failure behavior. When the rotation angle is close to the slope surface, it tends to amplify both the magnitude and variability of slope failure. Furthermore, the study evaluates the efficiency of generating these random fields and emphasizes the substantial computational speed improvements achieved with GPU acceleration. These findings offer a robust approach for probabilistic analysis of slope large deformations considering rotated anisotropy. They provide a theoretical foundation for accurately assessing the risk of slope collapse, holding significant practical implications for geotechnical engineering.
{"title":"Efficient Random Field Generation With Rotational Anisotropy for Probabilistic SPH Analysis of Slope Failure","authors":"Zhonghui Bi, Wei Wu, Liaojun Zhang, Chong Peng","doi":"10.1002/nag.3858","DOIUrl":"https://doi.org/10.1002/nag.3858","url":null,"abstract":"Due to geological processes such as sedimentation, tectonic movement, and backfilling, natural soil often exhibits characteristics of rotated anisotropy. Recent studies have shown the significant impact of rotated anisotropy on slope stability. However, little research has explored how this rotated anisotropy affects the large deformations occurring after slope failure. Therefore, this study integrates rotated random field theory with smoothed particle hydrodynamics (SPH) to investigate its influence on post‐failure slope behavior. Focusing on a typical slope scenario, this research utilizes graphics processing unit (GPU)–accelerated covariance matrix decomposition (CMD) method to create rotated anisotropy random fields and applies the SPH framework for analysis. It examines the influence of rotated anisotropy angles and the cross‐correlation between cohesion and internal friction angle on landslides. The results indicate that the rotational anisotropy of the slope significantly influences post‐failure behavior. When the rotation angle is close to the slope surface, it tends to amplify both the magnitude and variability of slope failure. Furthermore, the study evaluates the efficiency of generating these random fields and emphasizes the substantial computational speed improvements achieved with GPU acceleration. These findings offer a robust approach for probabilistic analysis of slope large deformations considering rotated anisotropy. They provide a theoretical foundation for accurately assessing the risk of slope collapse, holding significant practical implications for geotechnical engineering.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142384210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leonardo C. Mesquita, Elisa D. Sotelino, Matheus L. Peres
The present work proposes a new version of the Green‐FOSM (first‐order second moment) method, which eliminates the iterative calculation process of the original version and, simultaneously, solves the convergence problems related to the mechanical properties of rocks that form the geological formation. In this calculation scheme, the iterative process is eliminated by using a matrix that correlates the nodal displacement vector with the strain vector. Considering the same computational resources, this non‐iterative version of the Green‐FOSM method is up to 200 times faster than the original iterative process. In addition, it allows analyzing problems with more than 10,000 random variables, value that in the original method is less than 3000. To demonstrate its validity, the proposed method is applied to two hypothetical models subjected to different fluid extraction processes. For all the different levels of correlation and spatial variability, the statistical results obtained by the proposed method agree well with the results obtained via Monte Carlo Simulation (MCS). The relationship between CPU times demonstrates that the proposed method is at least 50 times faster than MCS. In the end, the non‐iterative Green‐FOSM method is used to obtain the displacement, strain, and stress fields of a geological section constructed from a seismic image of Brazilian pre‐salt oil region. The results found show that, depending on the levels of spatial variability, the analyzed fields can assume values up to 30.6% higher or lower than the values obtained deterministically.
{"title":"Evaluation of the Spatial Variability of the Mechanical Properties of Rocks Using Non‐Iterative Green's Function Approach and the FOSM Method","authors":"Leonardo C. Mesquita, Elisa D. Sotelino, Matheus L. Peres","doi":"10.1002/nag.3861","DOIUrl":"https://doi.org/10.1002/nag.3861","url":null,"abstract":"The present work proposes a new version of the Green‐FOSM (first‐order second moment) method, which eliminates the iterative calculation process of the original version and, simultaneously, solves the convergence problems related to the mechanical properties of rocks that form the geological formation. In this calculation scheme, the iterative process is eliminated by using a matrix that correlates the nodal displacement vector with the strain vector. Considering the same computational resources, this non‐iterative version of the Green‐FOSM method is up to 200 times faster than the original iterative process. In addition, it allows analyzing problems with more than 10,000 random variables, value that in the original method is less than 3000. To demonstrate its validity, the proposed method is applied to two hypothetical models subjected to different fluid extraction processes. For all the different levels of correlation and spatial variability, the statistical results obtained by the proposed method agree well with the results obtained via Monte Carlo Simulation (MCS). The relationship between CPU times demonstrates that the proposed method is at least 50 times faster than MCS. In the end, the non‐iterative Green‐FOSM method is used to obtain the displacement, strain, and stress fields of a geological section constructed from a seismic image of Brazilian pre‐salt oil region. The results found show that, depending on the levels of spatial variability, the analyzed fields can assume values up to 30.6% higher or lower than the values obtained deterministically.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142384212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Plasticity and fracture problems have always been hot topics in numerical methods. In this work, a universal implementation procedure for the elasto‐plastic constitutive model is developed in the four‐dimensional lattice spring model (4D‐LSM), in which the Jaumann stress rate is incorporated to exclude the influence of the rigid rotation in the particle stress, expanding the ability of 4D‐LSM to deal with large elastic deformation problems by its own to large plastic deformation problems. As an example, the Zienkiewicz–Pande (ZP) constitutive model is implemented. Several numerical examples are carried out to check the performance of the implemented model. Through a comparison with analytical solutions, available experimental data, and other numerical results, the stability of the developed plastic framework and the correctness of the stress calculation scheme are verified. Meanwhile, numerical results show that the developed code is capable of solving elasto‐plastic large deformation problems. With the advantage of 4D‐LSM in handling fracture problems, the ability of the embedded model to solve plastic fracture problems is verified with a simple maximum deformation failure criterion.
{"title":"Implementation of the Zienkiewicz–Pande Model into a Four‐Dimensional Lattice Spring Model for Plasticity and Fracture","authors":"Xin‐Dong Wei, Zhe Li, Gao‐Feng Zhao","doi":"10.1002/nag.3860","DOIUrl":"https://doi.org/10.1002/nag.3860","url":null,"abstract":"Plasticity and fracture problems have always been hot topics in numerical methods. In this work, a universal implementation procedure for the elasto‐plastic constitutive model is developed in the four‐dimensional lattice spring model (4D‐LSM), in which the Jaumann stress rate is incorporated to exclude the influence of the rigid rotation in the particle stress, expanding the ability of 4D‐LSM to deal with large elastic deformation problems by its own to large plastic deformation problems. As an example, the Zienkiewicz–Pande (ZP) constitutive model is implemented. Several numerical examples are carried out to check the performance of the implemented model. Through a comparison with analytical solutions, available experimental data, and other numerical results, the stability of the developed plastic framework and the correctness of the stress calculation scheme are verified. Meanwhile, numerical results show that the developed code is capable of solving elasto‐plastic large deformation problems. With the advantage of 4D‐LSM in handling fracture problems, the ability of the embedded model to solve plastic fracture problems is verified with a simple maximum deformation failure criterion.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142369109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pengchang Wei, Weiwei Niu, Chi Yao, Zhenyu He, Yuan‐Yuan Zheng, Wei Ma
The ice–water phase transition of bulk ice could develop with varying temperatures and external loads, significantly affecting its mechanical properties. The coupling effect of temperature and shear loads on the thermo‐mechanical properties of bulk ice and its phase transition evolution is poorly understood, especially at the nanoscale. In this study, molecular dynamics (MD) simulation method was employed to investigate the thermo‐mechanical behaviours of bulk ice‐Ih system at the microscale under various temperatures (73–270 K) and shear paths, where its phase transition, elastic properties, structure deformation mechanism and structural anisotropy were discussed. The simulation results show that (1) the shear modulus, shear strength and ultimate shear strain of bulk ice‐Ih system could linearly decrease with rising temperature, aligning with previous studies. (2) Two types of failure modes from bulk ice‐Ih system were founded, such as solid–liquid phase co‐existence at 73–225 K and liquid phase at 250–270 K. (3) Ice melting into water was attributed to the fracture of hydrogen bond during shear process. (4) Compared to vertical shearing (XZ () and YZ ()) directions, the mechanical response along the horizontal shearing (XY (0001)) direction was most sensitive to temperature effect.
块冰的冰水相变会随着温度和外部载荷的变化而发生，从而对其机械特性产生重大影响。人们对温度和剪切载荷对块冰的热机械特性及其相变演化的耦合效应知之甚少，尤其是在纳米尺度上。本研究采用分子动力学（MD）模拟方法研究了块冰-Ih 体系在不同温度（73-270 K）和剪切路径下的微尺度热机械行为，讨论了其相变、弹性特性、结构变形机制和结构各向异性。模拟结果表明：（1）块冰-Ih 体系的剪切模量、剪切强度和极限剪切应变随温度升高呈线性下降，这与之前的研究结果一致。(2) 建立了两种块冰-Ih 体系失效模式，如 73-225 K 时的固液相共存和 250-270 K 时的液相共存。(4) 与垂直剪切（XZ（）和 YZ（））方向相比，沿水平剪切（XY（0001））方向的力学响应对温度效应最为敏感。
{"title":"Microscopic Thermo‐Mechanical Properties and Phase Transition of Bulk Ice‐Ih","authors":"Pengchang Wei, Weiwei Niu, Chi Yao, Zhenyu He, Yuan‐Yuan Zheng, Wei Ma","doi":"10.1002/nag.3856","DOIUrl":"https://doi.org/10.1002/nag.3856","url":null,"abstract":"The ice–water phase transition of bulk ice could develop with varying temperatures and external loads, significantly affecting its mechanical properties. The coupling effect of temperature and shear loads on the thermo‐mechanical properties of bulk ice and its phase transition evolution is poorly understood, especially at the nanoscale. In this study, molecular dynamics (MD) simulation method was employed to investigate the thermo‐mechanical behaviours of bulk ice‐Ih system at the microscale under various temperatures (73–270 K) and shear paths, where its phase transition, elastic properties, structure deformation mechanism and structural anisotropy were discussed. The simulation results show that (1) the shear modulus, shear strength and ultimate shear strain of bulk ice‐Ih system could linearly decrease with rising temperature, aligning with previous studies. (2) Two types of failure modes from bulk ice‐Ih system were founded, such as solid–liquid phase co‐existence at 73–225 K and liquid phase at 250–270 K. (3) Ice melting into water was attributed to the fracture of hydrogen bond during shear process. (4) Compared to vertical shearing (<jats:italic>XZ</jats:italic> () and <jats:italic>YZ</jats:italic> ()) directions, the mechanical response along the horizontal shearing (<jats:italic>XY</jats:italic> (0001)) direction was most sensitive to temperature effect.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142374122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elodie Donval, Ghazi Hassen, Duc Toan Pham, Patrick de Buhan, Martin Vigroux
The present contribution proposes a new semi‐analytical homogenisation approach to determine a running‐bond masonry wall's in‐ and out‐of‐plane strength domain based on the yield design framework. The main novelty of such an approach is that it does not rely on simplifying assumptions such as infinitely thin joints or plane stress state within the blocks, by making use of 3D virtual failure mechanisms in the kinematic approach. The new semi‐analytical approach is then compared to a state‐of‐the‐art numerical implementation of the kinematic approach of yield design, relying on semi‐definite programming. Several comparisons show a good agreement between the semi‐analytical and the numerical approaches and outline the computational efficiency of the semi‐analytical approach as well as the fact that it is very well suited for engineering design purposes. Both proposed approaches are then compared to existing approaches based on the limit analysis or yield design framework.
{"title":"3D Semi‐Analytical and Numerical Upper‐Bound Homogenisation Approaches to the Out‐of‐Plane Strength Domain of a Running‐Bond Masonry Wall","authors":"Elodie Donval, Ghazi Hassen, Duc Toan Pham, Patrick de Buhan, Martin Vigroux","doi":"10.1002/nag.3851","DOIUrl":"https://doi.org/10.1002/nag.3851","url":null,"abstract":"The present contribution proposes a new semi‐analytical homogenisation approach to determine a running‐bond masonry wall's in‐ and out‐of‐plane strength domain based on the yield design framework. The main novelty of such an approach is that it does not rely on simplifying assumptions such as infinitely thin joints or plane stress state within the blocks, by making use of 3D virtual failure mechanisms in the kinematic approach. The new semi‐analytical approach is then compared to a state‐of‐the‐art numerical implementation of the kinematic approach of yield design, relying on semi‐definite programming. Several comparisons show a good agreement between the semi‐analytical and the numerical approaches and outline the computational efficiency of the semi‐analytical approach as well as the fact that it is very well suited for engineering design purposes. Both proposed approaches are then compared to existing approaches based on the limit analysis or yield design framework.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142369084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xudong Zhao, Jie Min, Shaolin Ding, Yang Liu, Jiaxin Liao, Shuai Zhang
Existing solutions for electro‐osmotic consolidation assume a linear voltage distribution, which is inconsistent with the experimental findings. The present study introduces a novel two‐dimensional electro‐osmotic consolidation model for unsaturated soils, which considers the influence of non‐linear voltage distribution. The closed‐form solution is derived by employing the eigenfunction expansion method and the Laplace transform technique. The accuracy of the analytical solutions is validated through the implementation of finite element simulations. The findings from the parametric studies indicate that the excess pore water pressure (EPWP) observed in electro‐osmotic consolidation is influenced by the distribution of voltage. The dissipation rate of EPWP is observed to be higher when subjected to non‐linear voltage conditions compared to linear voltage conditions. Moreover, the impact of non‐linear voltage distribution becomes more pronounced in unsaturated soil characterised by higher electro‐osmosis conductivity and a lower ratio of kx/ky. In contrast, the excess pore air pressure (EPAP) remains unaffected by the voltage distribution.
{"title":"Analytical Solution for 2D Electro‐Osmotic Consolidation of Unsaturated Soil With Non‐linear Voltage Distribution","authors":"Xudong Zhao, Jie Min, Shaolin Ding, Yang Liu, Jiaxin Liao, Shuai Zhang","doi":"10.1002/nag.3854","DOIUrl":"https://doi.org/10.1002/nag.3854","url":null,"abstract":"Existing solutions for electro‐osmotic consolidation assume a linear voltage distribution, which is inconsistent with the experimental findings. The present study introduces a novel two‐dimensional electro‐osmotic consolidation model for unsaturated soils, which considers the influence of non‐linear voltage distribution. The closed‐form solution is derived by employing the eigenfunction expansion method and the Laplace transform technique. The accuracy of the analytical solutions is validated through the implementation of finite element simulations. The findings from the parametric studies indicate that the excess pore water pressure (EPWP) observed in electro‐osmotic consolidation is influenced by the distribution of voltage. The dissipation rate of EPWP is observed to be higher when subjected to non‐linear voltage conditions compared to linear voltage conditions. Moreover, the impact of non‐linear voltage distribution becomes more pronounced in unsaturated soil characterised by higher electro‐osmosis conductivity and a lower ratio of <jats:italic>k<jats:sub>x</jats:sub>/k<jats:sub>y</jats:sub></jats:italic>. In contrast, the excess pore air pressure (EPAP) remains unaffected by the voltage distribution.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents a novel approach of intelligent parameter identification (IPI) for a high‐cycle accumulation (HCA) model of sand, which reduces the subjective errors on manual parameter calibration and makes the use of the HCA model more accessible. The technique is based on optimization theory and adopts the cuckoo search algorithm (CSA). To improve search ability and convergence speed of CSA, several enhancements are implemented. First, the improved CSA (ICSA) incorporates quasi‐opposition learning to expand the search space and replaces the original search strategy with a Cauchy random walk to enhance global search ability. Second, an adaptive scaling factor is introduced in the algorithm's control parameters to achieve a better balance between exploration speed and accuracy. Third, a dynamic inertia weight is used to balance the search between global and local spaces when generating new nest positions after abandoning old ones. The performance of the ICSA‐based IPI approach is evaluated by comparing it with the original CSA‐based IPI and manual calibration in determining the HCA model parameters. A comprehensive analysis is also conducted to assess the effectiveness and superiority of each improvement strategy introduced in the ICSA over the original CSA. All comparisons demonstrate that the proposed ICSA‐based IPI method is more powerful and efficient in finding optimal parameters.
{"title":"Intelligent Parameter Identification for a High‐Cycle Accumulation Model of Sand With Enhancement of Cuckoo Search Algorithm","authors":"Shao‐Heng He, Zhen‐Yu Yin, Yifei Sun, Zhi Ding","doi":"10.1002/nag.3838","DOIUrl":"https://doi.org/10.1002/nag.3838","url":null,"abstract":"This study presents a novel approach of intelligent parameter identification (IPI) for a high‐cycle accumulation (HCA) model of sand, which reduces the subjective errors on manual parameter calibration and makes the use of the HCA model more accessible. The technique is based on optimization theory and adopts the cuckoo search algorithm (CSA). To improve search ability and convergence speed of CSA, several enhancements are implemented. First, the improved CSA (ICSA) incorporates quasi‐opposition learning to expand the search space and replaces the original search strategy with a Cauchy random walk to enhance global search ability. Second, an adaptive scaling factor is introduced in the algorithm's control parameters to achieve a better balance between exploration speed and accuracy. Third, a dynamic inertia weight is used to balance the search between global and local spaces when generating new nest positions after abandoning old ones. The performance of the ICSA‐based IPI approach is evaluated by comparing it with the original CSA‐based IPI and manual calibration in determining the HCA model parameters. A comprehensive analysis is also conducted to assess the effectiveness and superiority of each improvement strategy introduced in the ICSA over the original CSA. All comparisons demonstrate that the proposed ICSA‐based IPI method is more powerful and efficient in finding optimal parameters.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An analytical solution based on the infinite layer theory of Novak and Biot's consolidation equation is developed in this study to evaluate the impact of local debonding occurring at the pile–soil interface. The potential functions are employed to decouple the differential equations that govern the soil deformations, while the dynamic resistances of soil are determined from the boundary conditions at the pile–soil interface in accordance with computational theory for mixed boundary problems. The Adomian decomposition method is introduced to obtain the dynamic impedances of pile. The effects of local debonding on the dynamic resistances of soil are investigated by comparing the results from the present solution with available schemes based on perfect contact assumption. The influences of pile–soil modulus ratio, exciting frequency, soil permeability, and slenderness ratio of pile while considering local debonding were then examined. The numerical results indicate that the local debonding occurring at the pile–soil interface dramatically weakened the lateral dynamic impedances of pile, and this trend was particularly pronounced at high frequency and small modulus ratio. Additionally, the local debonding phenomenon also imposes limitations on the implementation of the equivalent single‐phase solution in practical engineering applications. The presented solution theoretically demonstrates the significant impact of local debonding on the dynamic response of piles embedded in saturated soil and may provide insight into determining parameter values in empirical equations.
{"title":"Lateral Dynamic Impedances of Pile Embedded in Saturated Soil Considering Local Debonding at the Pile–Soil Interface","authors":"Nansheng Ding, Zhaowei Ding, Qihua Zhao","doi":"10.1002/nag.3849","DOIUrl":"https://doi.org/10.1002/nag.3849","url":null,"abstract":"An analytical solution based on the infinite layer theory of Novak and Biot's consolidation equation is developed in this study to evaluate the impact of local debonding occurring at the pile–soil interface. The potential functions are employed to decouple the differential equations that govern the soil deformations, while the dynamic resistances of soil are determined from the boundary conditions at the pile–soil interface in accordance with computational theory for mixed boundary problems. The Adomian decomposition method is introduced to obtain the dynamic impedances of pile. The effects of local debonding on the dynamic resistances of soil are investigated by comparing the results from the present solution with available schemes based on perfect contact assumption. The influences of pile–soil modulus ratio, exciting frequency, soil permeability, and slenderness ratio of pile while considering local debonding were then examined. The numerical results indicate that the local debonding occurring at the pile–soil interface dramatically weakened the lateral dynamic impedances of pile, and this trend was particularly pronounced at high frequency and small modulus ratio. Additionally, the local debonding phenomenon also imposes limitations on the implementation of the equivalent single‐phase solution in practical engineering applications. The presented solution theoretically demonstrates the significant impact of local debonding on the dynamic response of piles embedded in saturated soil and may provide insight into determining parameter values in empirical equations.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiao Wang, Fusheng Zha, Hamid Rajabi, Long Xu, Huaxiang Yan
Landfills emissions, ranking as the third‐largest anthropogenic source of methane in the atmosphere, pose environmental challenges and threaten public health. The pivotal role of clay as a mitigating agent for methane emission within landfill cover systems cannot be overstated; however, our understanding of methane escape from fractured clay remains limited. This study aims to address the existing gaps by proposing a robust analytical model of methane transport in both fractures and clay matrix. Our investigation also includes a dimensionless analysis to govern the relative significance of diffusion and advection in methane emission from fractured clay, systematically reviewing factors such as the degree of water saturation (Sr) and fracture width. The methane concentration profiles in cracked clay demonstrated escalating sensitivity to Péclet (Pe) numbers, especially when advection dominates transport. Our findings also highlight the prevalence of preferential methane flow with increasing Sr in the clay matrix. The flux of methane emission from fractures at Sr = 0.8 was 130 times greater than that from intact clay. However, the study necessitates considering methane emission from clay matrix, particularly in dry clay conditions (Sr = 0.2 and 0.4). The accumulated methane emission flux from intact clay, more than that emitted from fractures by about 2.5 times at Sr = 0.2, was 1.3 × 10−5 g/m/s. The findings significantly advance the understanding of gas transport in fractured geomaterials, revealing the effect of water saturation and crack width on methane emissions from fractures. Overall, the outcomes emphasize the inclusion importance of methane emission from cracked clay in the design of gas barriers.
垃圾填埋场排放的甲烷是大气中第三大人为来源，对环境构成挑战，并威胁着公众健康。在垃圾填埋场覆盖系统中，粘土作为甲烷排放的缓解剂，其关键作用怎么强调都不为过；然而，我们对甲烷从断裂粘土中逸出的了解仍然有限。本研究旨在通过提出一个可靠的甲烷在裂缝和粘土基质中迁移的分析模型来弥补现有的不足。我们的研究还包括一项无量纲分析，以确定甲烷从裂缝粘土中排放时扩散和平流的相对重要性，并系统地审查了水饱和度（Sr）和裂缝宽度等因素。裂缝粘土中的甲烷浓度剖面显示出对佩克莱特（Pe）数的敏感性不断上升，尤其是当平流在传输中占主导地位时。我们的研究结果还突出表明，随着粘土基质中 Sr 的增加，甲烷会优先流动。当 Sr = 0.8 时，从裂缝中排放的甲烷流量比从完整粘土中排放的甲烷流量大 130 倍。不过，这项研究有必要考虑粘土基质的甲烷排放，尤其是在干燥粘土条件下（Sr = 0.2 和 0.4）。在 Sr = 0.2 时，完整粘土的甲烷累积排放通量为 1.3 × 10-5 g/m/s，是裂缝排放通量的约 2.5 倍。研究结果极大地推动了对断裂土工材料中气体传输的理解，揭示了水饱和度和裂缝宽度对裂缝甲烷排放的影响。总之，研究结果强调了在设计气体屏障时将裂缝粘土中的甲烷排放纳入其中的重要性。
{"title":"Decoding Methane Flow in Fractured Clay: A Semi‐Analytical Model With Matrix Diffusion and Advection","authors":"Qiao Wang, Fusheng Zha, Hamid Rajabi, Long Xu, Huaxiang Yan","doi":"10.1002/nag.3853","DOIUrl":"https://doi.org/10.1002/nag.3853","url":null,"abstract":"Landfills emissions, ranking as the third‐largest anthropogenic source of methane in the atmosphere, pose environmental challenges and threaten public health. The pivotal role of clay as a mitigating agent for methane emission within landfill cover systems cannot be overstated; however, our understanding of methane escape from fractured clay remains limited. This study aims to address the existing gaps by proposing a robust analytical model of methane transport in both fractures and clay matrix. Our investigation also includes a dimensionless analysis to govern the relative significance of diffusion and advection in methane emission from fractured clay, systematically reviewing factors such as the degree of water saturation (<jats:italic>Sr</jats:italic>) and fracture width. The methane concentration profiles in cracked clay demonstrated escalating sensitivity to Péclet (<jats:italic>Pe</jats:italic>) numbers, especially when advection dominates transport. Our findings also highlight the prevalence of preferential methane flow with increasing <jats:italic>Sr</jats:italic> in the clay matrix. The flux of methane emission from fractures at <jats:italic>Sr</jats:italic> = 0.8 was 130 times greater than that from intact clay. However, the study necessitates considering methane emission from clay matrix, particularly in dry clay conditions (<jats:italic>Sr</jats:italic> = 0.2 and 0.4). The accumulated methane emission flux from intact clay, more than that emitted from fractures by about 2.5 times at <jats:italic>Sr</jats:italic> = 0.2, was 1.3 × 10<jats:sup>−5</jats:sup> g/m/s. The findings significantly advance the understanding of gas transport in fractured geomaterials, revealing the effect of water saturation and crack width on methane emissions from fractures. Overall, the outcomes emphasize the inclusion importance of methane emission from cracked clay in the design of gas barriers.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The long‐core SDCM pile is a typical type of stiffened deep cement mixing (SDCM) pile, it could be widely exploited in coastal geotechnical engineering because of its high bearing capacity, low settlement, green, and economic advantages. The long‐core SDCM pile is constituted by a PHC pipe pile and cemented soil, the height of the PHC pipe pile is upward than the depth of the cemented soil reinforcement. This study implements a theoretical approach to load transfer analysis of the long‐core SDCM pile under vertical load in layer soil. Herein, the shear constitutive models of the DCM pile‐PHC pipe pile interface and the fictitious soil pile‐PHC pipe pile interface are double exponential models, the compression constitutive model of the soil under the pile and the shear constitutive models of the DCM pile–soil interface and the fictitious soil pile–soil interface are ideal elastic–plastic models. The results obtained from this calculation model can match well with the data from on‐site tests and other analytical solutions. The theoretical model is used to analyze the key parameters LD/LP, DD/DP, Ec, and Ep of the long‐core SDCM pile. The LD/LP and DD/DP are the critical parameters affecting the bearing characteristics, and the minor settlement is affected by the changes of Ec and Ep.
{"title":"Theoretical Analysis and Field Investigation on Bearing Characteristics of the Long‐Core SDCM Pile Under Vertical Load in Multilayered Soil","authors":"Zhiyu Gong, Guoliang Dai, Hongbo Liu, Xinsheng Chen, Haoran Ouyang, Jianxiong Jiang","doi":"10.1002/nag.3835","DOIUrl":"https://doi.org/10.1002/nag.3835","url":null,"abstract":"The long‐core SDCM pile is a typical type of stiffened deep cement mixing (SDCM) pile, it could be widely exploited in coastal geotechnical engineering because of its high bearing capacity, low settlement, green, and economic advantages. The long‐core SDCM pile is constituted by a PHC pipe pile and cemented soil, the height of the PHC pipe pile is upward than the depth of the cemented soil reinforcement. This study implements a theoretical approach to load transfer analysis of the long‐core SDCM pile under vertical load in layer soil. Herein, the shear constitutive models of the DCM pile‐PHC pipe pile interface and the fictitious soil pile‐PHC pipe pile interface are double exponential models, the compression constitutive model of the soil under the pile and the shear constitutive models of the DCM pile–soil interface and the fictitious soil pile–soil interface are ideal elastic–plastic models. The results obtained from this calculation model can match well with the data from on‐site tests and other analytical solutions. The theoretical model is used to analyze the key parameters <jats:italic>L</jats:italic><jats:sub>D</jats:sub>/<jats:italic>L</jats:italic><jats:sub>P</jats:sub>, <jats:italic>D</jats:italic><jats:sub>D</jats:sub>/<jats:italic>D</jats:italic><jats:sub>P</jats:sub>, <jats:italic>E</jats:italic><jats:sub>c</jats:sub>, and <jats:italic>E</jats:italic><jats:sub>p</jats:sub> of the long‐core SDCM pile. The <jats:italic>L</jats:italic><jats:sub>D</jats:sub>/<jats:italic>L</jats:italic><jats:sub>P</jats:sub> and <jats:italic>D</jats:italic><jats:sub>D</jats:sub>/<jats:italic>D</jats:italic><jats:sub>P</jats:sub> are the critical parameters affecting the bearing characteristics, and the minor settlement is affected by the changes of <jats:italic>E</jats:italic><jats:sub>c</jats:sub> and <jats:italic>E</jats:italic><jats:sub>p</jats:sub>.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142325568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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